Duplicating



Patented Oct. 26, 1926.

UNITED STATES ARMAND DE WAELE, OF LONDON,

ENGLAND, AS$IGNOR TO D. GES'IETNER, LIMITED, OF LONDON, ENGLAND.

DUPLICATING.

No Drawing. Application filed June 15, 1923, Serial No. 645,707, and inGreat Britain April 12, 1923.

body, and which do not need moistening or softening prior to cutting thestencil by means of a typewriter or style.

Stencil sheets of the kind in question having a stencil layer of thecharacter indicated formed from gelatinizing organic colloids which arepeptized or dispersed in organic solvents and also others. in whichcolloids. for instance gelatine, which are peptized or dispersed in anaqueous medium are present, although organic solvents have in this casebeen usedin forming the coating composition, are known. The employmentof organic solvents is, however, open to objection on account of expenseand, further, stencil sheets of the kind specified formed from agelatinizing organic colloid dispersible in an aqueous medium ashitherto produced have been found to be unsatisfactory.

The object of the present invention is to provide improvements inconnection with stencil sheets-of the kind specified.

According to the present invention the main tempering agent is presentin the composition, of which the stencil layer is constituted, prior tothe gelation thereof, in that degree of dispersion which is regarded ascharacteristic of the colloid state.

Thus, acording to the invention, the composition may comprise agelatinizing organr ic colloid dispersiblc in an aqueous medium and atempering agent of the class de-i scribed below which prior to thegelation of the composition is dispersed to the degree specified.

My investigations appear to show that the main tempering agent will bepresent in the composition after gelation in substantially the samedegree of dispersion but that such is the case I have not yet been ableto show definitely. However, it would appear to be characteristic of thegelated compositions constituting the stencil layer in accordance withthe present invention, that the tempermg agent is highly dispersedtherein and most probably dispersed to the degree con-x sldered to becharacteristic of the colloid state. ThlS high degree of dispersion Ihave found to be necessary for securing a highly sensitive stencil layerand at the same time a durable stencil.

In this connection it may be remarked that the tempering agents presentin certain compositions constituting known stencil layers may bedispersed in the material after gelation to the degree considered to becharacteristic of the colloid state, but if this is in fact the casethey have been present in the composition prior to gelation in the formof true or molecular solutions usually in the medium used for securingthe dispersion of the gelatinizing colloid.

The invention is not confined to the employment of particular organiccolloids which will gelatinize but it may be remarked that organiccolloids such as the protein colloids, which pepti'ze in aqueous media,may, in accordance with the invention, be employed in association withoilywaxy bodies or with waxy bodies and if necessary with an agentadapted to secure the dispersion of the latter to the degree aboveindicated.

The invention consists more particularly in a stencil sheet having astencil layer of the character specified broadly in the above precedingparagraph, in which the oily-waxy bodies or waxy bodies present are softor even liquid at the-ordinary temperature of the air.

The invention also extends to the process of forming stencil sheetswhich comprises applying to a porous support, for instance 'yoshinopaper, an emulsion from whichvolatile organic solvents are absent,comprising a gelatmizmg organic colloid dispersed in an aqueous medium,an oily-waxy body or waxy bodyand, if necessary, an agent adapted tosecure theemulsification of the latter in the organic colloid disperse.

Preferably, as emulsifying agents, sulphonated wax containing oil orsulphonated waxes and particularly the sulphonated oiland-wax mixturesor sulphonated liquid waxes or the sulphonation products of materialproportions of liquid waxes derived from marine animals are employed.

The liquid Waxes include the oil from the case of the true sperm whale,Pity seter macrocephalus, and the oil from the head cavity of thebottlenose whale, Hy peroorlon 'r'ostmt'us and Hy joeroodon (Hod-on,both oils being, it is believed, described in commerce as sperm oil.Other oils obtainable commercially, for instance the oil from theblubber of the whales above referred to, contain material proportions ofliquid waxes, and the products obtained by the sulphonation of such oilsare suitable for use.

Highly satisfactory results, may be secured in accordance with theinvention by using as the emulsifying agent sulphonated sperm oil whichmay also act as a tempering agent, and by the use of sperm oil as theoily or waxy constituent of the stencil layer or main tempering agent.The invention is, however,not confined to the use of sperm oil in thiscapacity as many other oils, ineluding for instance mineral oils, aresuitable for use in accordance with the invention. I

In this connection it may be remarked that the employment of Turkey' redoil in association with fatty bodies and gelatinizing organic colloids,such as gelatine, dispersed in water has been proposed in the productionof stencil sheets. I have found, however, that sulphonatedcastor oil andits derivatives. such as Monopol soap, are entirely unsuitable in thecircumstances heretofore prescribed for use in accordance with theinvention as they are incapable in such circumstances of securing thedispersion of the oily or fatty material throughout the gelatine or thelike to produce a product inwhich the oily-waxy or waxy material ispresent in a degree of sub-division comparable with that regarded asacharacteristic of colloid particles.

oily-waxy or waxy constituents are esent in thestencil layers inaccordance with the invention in such proportion that they constitutewholly or mainly the tempering agent for the organic colloid. such asgelatine,-'that'is.to say, the agent adapted so to modify the propertiesof the colloid that the structure of the stencil layer may' be 7 brokendown by the blows of the type when ;1'nsed in forming stencils in atypewriter or the style when producing a stencil by gland.

The proportion of the tempering agent I at it hav found 'it convenientto employ may 1 5 ry between six and ten parts to one of a "colloid,such as gelatine. This indication, however, is only given for thepurpose of illustrating the proportionl have found it convenient to useincertain atmospheric or climatic conditions.

An opaque pigment, the colour of which will contrast with the ink withwhich the stencil will be used, for instance a white pigment, may beincorporated in the stencil layer, as indicated in the specification ofthe co-pending application for Letters Patent No. 645.708 care beingtaken to select a pigment which does not operate to break down thestructure of the coating composition.

The coating of the porous material forming the base of the stencil sheetmay be effected in the usual manner by the employment of a trough orroller, the coated sheet being then dried Without, however, subjectingit to treatment which would cause the composition constituting thestencil layer to liquefy.

Further, the coated sheet may be formolized or otherwise treated toconvert the organic colloid, such as gelatine, present therein into theinsoluble or hardened form.

As is well known, gelatines vary considerably in their properties; forinstance. some ar more acid than others. It is therefore important toselect a gelatine, the properties of which are not inimical (inconsequence, for example, of the presence of impurities in it) to theformation of a-stable colloid when it is brought together with the oilyor waxy bodies and the emulsifying agent.

The-following particulars are given by way of example to illustrate asuitable method of carrying the inventionintoeffect.

A coating composition isv prepared by mixing 150 parts of a 10% aqueoussolution of gelatine with 25 parts of sulphonated sperm oil and 75 partsof sperm oil and adding 20 parts of a composite White titanium oxidepigment. The composition when uniform and diluted to a suitableviscosity is introduced into the tank of a coating machine of the kindin which the material to be coated is drawn over a roller partlyimmersed in the coating composition, meanwhile maintaining the comosition at a-temperature substantially over its gelating temperature,for example, F. to 140 F.

The coated sheets are then allowed to dry, care being taken to avoidliquefying the composition during this operation.

The coated sheets may then be formolized by passing them through achamber in which an atmosphere containing formaldehyde is maintained,

It is to be understood that the expressions employed herein inattempting to define the scope of the invention may by further researchbe found inappropriate; they are, however, believed to be suflicient todefine the invention in accordance with current conceptions in the try.1'?" A Further, as used in the claims, the expression oily body includesbodies which are in fact waxes or contain material proporlmpf physicalchemis q tions of waxes and sulphonated wax and sulphonated liquid waxinclude products obtained by the sulphonation of oils con-' tainingmaterial pro ortions of wax.

Having now descri ed my invention, what I claim as new, and desire tosecure by Letters Patent is 1. A stencil sheet for use in duplicatingmanuscript and typewritten documents, drawings and the like, comprisinga stencil layer in the form of a disperse system including a gelatinizedorganic colloid deposited from anaqueous medium, an oily body as themain tempering agent and a sulfonated material containing a sulfonatedwax adapted to secure the desired degree of dispersion of the oily bodyin the stencil layer. I

2. A stencil sheet for use in duplicatin manuscript and typewritten fdocuments drawings and the like, comprising a stencil layer in the formof a disperse system .including a gelatinized organic colloid depositedfrom an aqueous medium, an oily body as the main tempering agent and asulphonated wax.

3. A-stencil sheet for use in duplicating manuscript and typewrittendocuments, drawings and the like, comprising a stencil layer in the formof a disperse system including a gelatinized organic colloid depositedfrom an aqueous medium, an oily body as the main tempering agent and aSulphonated liquid wax.

4. The process of forming stencil sheets which comprises applying to aporous support, for instance yoshino paper, an emulsion from whichvolatile organic solvents are absent, comprising a gelatinizing organiccolloid dispersed in an .aqueous medium, an oily bodyfiin' a proportionconsiderably in excess of the said colloid, and functioningas the maintempering agent, and a sulphonated wax. I

5. The process of forming stencil sheets which comprisesapplying to aporous support, for instance yoshin'o paper, an emulsion from whichvolatile organic solvents are absent, comprising a gelatinizing organiccolloid dispersed in an aqueous medium,

an oily body in a proportion considerably in excess of the said colloid,and fimctioning as the main tempering agent, and a sulphonated liquidwax.

6. The process of forming stencil'sheets which comprises applying to aporous support, for instanceyoshino paper, an emulsion from whichvolatile organic solvents are absent, comprising a gelatinizing organiccolloid dispersed in an aqueous medium, an oily body in a proportionconsiderably in excess of the said colloid, and function

